This invention relates to roll-up type door assemblies which are generally used in commercial and industrial applications, elongate guides for use in these door assemblies, and curtain locks for retaining edge sections of the flexible door curtains used in these door assemblies.
It is well known in the door industry to provide a flexible, roll-up door that can be used to provide a passageway barrier in industrial, commercial, mining and other such facilities to accommodate the access of trucks, trains, forklifts and other such equipment to the facility or building or to provide passageway barriers within the facility or building.
A flexible roll-up door typically consists of a synthetic rubber or fabric curtain which acts as a barrier across the passageway. The curtain is attached across its top edge to a rigid steel pipe spanning the width of the passageway. This steel pipe is typically known as a drive barrel and is equipped with a solid steel shaft at both ends. Each of the two steel shafts are supported by a flanged type bearing attached to a steel plate, typically known as an endplate, which is attached to the, building structure directly above the passageway. Applying a controlled rotational movement of the drive barrel results in the curtain spooling onto the drive barrel, thus retracting the curtain upward to expose the passageway. Also, it may be inversely spooled off the drive barrel to dispense the curtain downward and close off the passageway.
The lower, horizontal perimeter or bottom of the curtain is reinforced with structural steel members to provide rigidity to the section of curtain edge making contact with the ground. This component of a flexible roll-up door is typically known as a bottom bar and must be of sufficient rigidity to maintain adequate straightness of the curtain for the operation of the door. The bottom bar is configured to a predetermined mass to provide adequate gravitational force to pull the curtain to the ground. The bottom bar may include reversing, safety and/or sealing devices mounted thereon.
The two vertical perimeters or edge sections of the curtain usually travel within suitable enclosures mounted adjacent to the passageway on each side. This component is typically known as a guide and serves the purpose of maintaining the required position of the vertical edge of the curtain while permitting unrestricted travel during door operation. The curtain is most often configured along its vertical edges with appropriate components, hereto referred to as curtain locks, to mate with the guides. Many flexible roll-up doors are constructed so that a predetermined releasing force can-cause the curtain to disengage itself from the guide or guides, for example, when the curtain is impacted by a vehicle or other device. The curtain is both retracted by and dispensed from the drive barrel over the forward side of a horizontal, rigid steel pipe spanning the width of the passageway. This pipe is located above the passageway and in close proximity to the building structure to provide an upper horizontal perimeter seal to the passageway and further serves as a curtain positioning mechanism, aligning the curtain with the guides mounted to the vertical sides of the passageway. This steel pipe is typically known as an idler barrel and is equipped with a solid steel shaft at both ends. Each of the two steel shafts are supported by a flange type bearing attached to its respective mounting angle.
The known flexible roll-up door systems can also include various other components to complete their functionality such as a counterbalance system, often through the use of torsion springs and/or weights, an operating mechanism that may consist of a manual hoist and/or electric motor with gear and/or chain power transmission arrangement, along with other secondary components. Known roll-up doors are commonly equipped with a curtain that has an element or elements attached to the vertical edges of the curtain (forming a curtain lock or locks) that co-operate with fabricated, often elaborate, guide assemblies.
U.S. Pat. No. 5,392,836 which issued Feb. 28, 1995 to Rite Hite Corporation teaches the use of a series of hemispherical follower elements attached to side edge sections of the curtain of a roll-up type door. An external force can disengage these follower elements from the door guide by changing the relative dimension of the gap formed by the guide and the follower element or elements. This relative dimensional change is achieved by utilizing a multiple component, fabricated guide that is inherently incapable of precise production dimensioning and often becomes askew or out of alignment during service. Thus, it is believed that this known roll-up door system is incapable of precise operation and therefore lacks reliability.
U.S. Pat. No. 5,482,104 issued Jan. 9, 1996 to Dale Lichy also describes a multi-component guide assembly which an external force, such as an impact from a vehicle, can disassemble to provide disengagement of an edge section of the curtain from its respective guide assembly. In one embodiment, each side edge of the curtain is provided with a lock strip which is bonded to one surface of the side edge. The strip is relatively narrow in width and has a thickness about the same as that of the curtain. In a second version of the curtain, there is a lock strip on the outer surface of the curtain edge and a further lock strip on the inner surface so that the strips form double wind locks. The two strips are not aligned with each other with the strip on the outer surface being spaced laterally inwardly from the edge of the curtain and the other strip having its outer edge generally aligned with the side edge of the curtain.
It is an object of one aspect of the present invention to provide a novel roll-up type door assembly having a flexible curtain made of rubber, synthetic rubber or fabric material employing extruded guide members that are relatively easy to manufacture and install and that can be made at a reasonable cost and employing pairs of curtain lock members mounted on the side edge sections of the curtain which help hold the side edge sections of the curtain in the guide members.
It is an object of another aspect of the present invention to provide an elongate guide for use with a roll-up type door which can be manufactured relatively easily using known manufacturing techniques and at a reasonable cost and which is capable of engaging a curtain lock mechanism with interior concave surfaces in a manner so that the guide is capable of engaging the lock mechanism on both front and back sides of the curtain simultaneously.
It is an object of an additional aspect of this invention to provide an improved and novel door curtain lock for retaining an edge section of a flexible door curtain in a door guide, this lock being made of low friction, wear resistant plastics material and having a rounded exterior surface and an inner surface for mounting to a front or rear surface of the door curtain.